Friday 20 November 2009 14.08 EST
First published on Friday 20 November 2009 14.08 EST

The postal dispute could reignite next week if Royal Mail continues to stall over peace talks, sources close to the Communication Workers Union have warned.

The two sides began negotiations under the auspices of mediation service Acas this week but it is understood that little headway has been made. "So far, it's been a case of talks about talks," one source said. "If no progress is being made you can't rule out the union going back to strike action."

Next Thursday, the CWU will review what progress has been made after it called off strike action earlier this month in order to try to thrash out an agreement with Royal Mail over its modernisation programme.

If the union believes that the two sides are no closer to reaching a deal, it is expected to suspend the talks.

Further strike action before Christmas could also be announced as the ballot for industrial action which was passed by CWU members last month still remains in place.

The Guardian has also learned that Roger Poole, until recently the chairman of the Northern Ireland Parades Commission, has been appointed by the two sides to act as an independent mediator.

Poole, also a former assistant general secretary of the Unison union, began mediating on Thursday.

Four more days of talks are due next week, culminating in Thursday's review when the CWU – as well as Royal Mail and Poole – will assess how well negotiations are progressing.

Earlier this month, the two sides reached an "interim agreement" where the CWU committed to calling off industrial action in return for holding talks under Acas to agree how to implement a long term modernisation programme of the business.

This would cover the introduction of "walk sequencing machines" next year, the impact of modernisation on postal workers' workloads, pay and job security. The two sides have also committed themselves to local reviews of practices to resolve local disputes.

But it is understood that Royal Mail union members in London, where the industrial action was the most severe, remain particularly concerned over Royal Mail practices.

Royal Mail is far less efficient than its rivals and postal workers have to spend hours each day sorting mail by hand before beginning deliveries.

The company is introducing automatic sorting machines but the union argues that managers are using modernisation to push through working practices resulting in unreasonable workloads and hours for staff. There is also concern that the changes will lead to thousands of redundancies.

The interim agreement allows for a "period of calm" with the "intention of both parties to make significant progress by early December with the aim of concluding a final agreement by the end of 2009".